Impact of LCLU changes in coastal tropical regions under conditions of global climate change

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Monday, 18 January 2010
Jorge E. González, City College of New York, New York, NY; and D. E. Comarazamy

The overall goal of this project is to gain a better understanding of the climate changes due to the combined effects of land cover and land use (LCLU) changes, anthropogenic activity, and increasing global concentrations of green house gases (GHG) in tropical coastal areas, regions where global, regional and local climate phenomena converge. To achieve the high-level research goal of improving our understanding of these combined climate effects (LCLU + GHG), the heavy populated island of Puerto Rico, in the Caribbean, was taken as the testing case. The research uses an integrated approach of high-resolution remote sensing and climatological data, linked to the Regional Atmospheric Modeling System (RAMS), which was employed to perform ensembles of climate simulations (combining 2-LCLU and 2-global climate scenarios). Reconstructed agricultural maps (1951-1956) are used to define past LCLU, and combined with reconstructed sea surface temperatures (SST) for the same period form the Past climate scenario, while the present (2000-2004) scenario was supported with the high resolution remote sensing data (10-m-res). The climate reconstruction approach is validated with actual data from the past. The selection of the past and present climate scenarios considers large-scale bias (i.e. ENSO/NAO) as reflected in the region of interest. Direct and cross comparison of the results is allowing quantifying single, combined, and competitive effects. Results indicate that global GHG have dominant effects on minimum temperatures (following regional tendencies), while urban sprawl dominates maximum temperatures with sea breezes responding to these changing gradients. Changes in precipitation are seasonal; GHG dominating rainfall seasons, and LCLU dry seasons. Forestation of past agricultural areas have an overwhelmingly mitigation effect on.